Recently, digital watermarking has attracted attention as a possible solution for multimedia copyright protection. Digital watermarking is a process of embedding copyright and/or other identifying information in multimedia data such as songs, videos, graphics, publications and otherwise. Such digital watermarks may range from being readily visible to a person's naked eye to invisible. Digital watermarks may be used for a variety of content identification, notification, piracy prevention and other purposes. In many implementations today, digital watermarks are limited to only a single rendering, duplication, presentation, production or otherwise of a given work of multimedia data. Similarly, in many implementations today, digital watermarks may not be robust to piracy attempts, such as may occur by the reorientation of a work from its original intended form to a form which prohibits or significantly interferes with the detection and/or identification of a digital watermark. Likewise, in many implementations today, digital watermarks may be visibly or readily identifiable using known techniques, e.g., opaque, to a potential pirate or other unauthorized user of the underlying digital content. Such opacity may result in the detection, deletion and/or modification of such digital watermark, thereby, hampering anti-piracy efforts and enforcement, royalty calculations and other efforts related to the authorized and unauthorized use of marked digital multimedia content. Thus, to be effectively used for the copyright protection and other purposes, digital watermarking should be unobtrusive, identifiable by those needing to so identify and robust against piracy and otherwise. Unobtrusiveness means that watermark embedding should not affect the quality of data. Identifiable means that a person knowing of the existence and characteristics of a digital watermark can readily detect the same and identify the origin of the content, as watermarked, at a given and/or desired point along the multi-media content's production (both pre and post), distribution and/or reproduction life cycle. Robustness refers to the requirement that embedded watermarks should be detected reliably even after some attacks.
The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded as subject matter by which the scope of the invention as defined in the claims is to be bound.